Belongs within: Neostegalia.
Contains: Lepospondyli, Synapsida, Reptilia.

The Reptiliomorpha are the group of animals more closely related to modern amniotes (reptiles and mammals) than to modern batrachians (frogs and salamanders). As well as the amniotes themselves, reptiliomorphs include the Carboniferous and Permian ‘anthracosaurs’ and lepospondyls, two groups traditionally classed as amphibians. Commonly regarded as the sister group of amniotes are the Diadectomorpha of the Late Carboniferous to Early Permian, some members of which reached large sizes such as the herbivorous Diadectidae. The Seymouriamorpha are a primarily Permian group that have been described as reptile-like but which retained some plesiomorphic features such as external gills.

Batrachosauria [Diadecta, Gymnodermia]LR95
    |--Seymouriamorpha [Discosauriscidae, Kotlassiidae, Seymouriida]RCQ03
    |    |  i. s.: NyctiboetusL00
    |    |         BiarmicaL00
    |    |         Urumqia liudaowanensisBS00, L00
    |    |--Seymouriidae [Karpinskiodauridae]M06
    |    |    |  i. s.: Buzulukia butsuri V’yushkov 1957TT05
    |    |    |--+--Karpinskiosaurus ultimus (Chudinov & V’yushkov 1956)DS20, TT05
    |    |    |  `--Kotlassia prima Amalitsky 1921DS20, RCQ03 [incl. Karpinskiosaurus secundus Ivakhnenko 1987L00, TT05]
    |    |    `--Seymouria White 1939DS20, D07
    |    |         |--S. agilisL00
    |    |         |--S. baylorensis Broili 1904RCQ03
    |    |         |--S. grandisL00
    |    |         `--S. sanjuanensis Vaughn 1966RCQ03
    |    `--+--DiscosauriscusDS20
    |       |    |--D. austriacus (Makowsky 1876)RCQ03
    |       |    |--D. netschaevi (Riabinin 1911)M93
    |       |    `--D. pulcherrimusL00
    |       `--+--Ariekanerpeton sigaloviDS20, L00
    |          `--+--Utegenia schpinari Kuznetzov & Ivakhnenko 1981DS20, M93
    |             `--+--Microphon exiguus Ivakhnenko 1983DS20, TT05
    |                `--LeptorophidaM93
    |                     |--Enosuchus [Enosuchidae]M93
    |                     |    `--E. breviceps (Konzhukova 1955)TT05
    |                     `--LeptorophidaeM93
    |                          |--Leptoropha talonophora (Tchudinov 1955)DS20, M93
    |                          `--RaphanodonM93
    |                               |--R. tverdochlebovae Ivakhnenko 1987M93
    |                               `--R. ultimus (Tchudinov & Viushkov 1956)M93
         |  |--Opisthodontosaurus carrolliPS17
         |  `--Westlothiana Smithson 1989RCQ03, D07
         |       `--W. lizziae Smithson & Rolfe 1990RCQ03
         `--Cotylosauria [Diadectomorpha, Reptiliomorpha]RCQ03
              |--Limnoscelidae [Limnosceloidea]M06
              |    |--Romeriscus periallus Baird & Carroll 1967M93
              |    `--LimnoscelisDS20
              |         |--L. dynatisM06
              |         `--L. paludis Williston 1911RCQ03
              `--+--+--Tseajaia [Tseajaiidae]DS20
                 |  |    `--T. campi Vaughn 1964RCQ03
                 |  `--+--Orobates pabstiDS20, SBM11
                 |     `--DiadectidaeM06
                 |          |--HelodectesC07
                 |          |    |--H. isaciiC07
                 |          |    `--H. paridensC07
                 |          |--DesmatodonM93
                 |          |    |--D. hesperis Vaughn 1969M93
                 |          |    `--D. hollandi Case 1908M93
                 |          |--Diadectes Watson 1917DS20, D07
                 |          |    |--D. absitus Berman, Sumida & Martens 1998RCQ03
                 |          |    |--D. phaseolinusC07
                 |          |    `--D. sideropelicusC07
                 |          `--EmpedoclesC07
                 |               |--E. alatusC07
                 |               |--E. latibuccatusC07
                 |               `--E. molarisC07
                 `--Amniota [Euamniota, Haemothermia, Mononaralia]RCQ03
                      |  i. s.: Cynodraco majorC07
                      |         Cynosuchus suppostusS01
                      |         NythosaurusC07
                      |         Scalaposaurus constrictusS01
                      |         Otocoelidae [Chelydosauridae]C07
                      |           |--OtocoelusC07
                      |           `--ConodectesC07
                      |         Eurycarpus oweniS01

*Type species of generic name indicated


[BS00] Boy, J. A., & H.-D. Sues. 2000. Branchiosaurs: larvae, metamorphosis and heterochrony in temnospondyls and seymouriamorphs. In: Heatwole, H., & R. L. Carroll (eds) Amphibian Biology vol. 4. Palaeontology. The evolutionary history of amphibians pp. 1150–1197. Surrey Beatty & Sons.

[C07] Case, E. C. 1907. Revision of the Pelycosauria of North America. Carnegie Institute of Washington Publication 55: 1–176, 35 pls.

[DS20] Daza, J. D., E. L. Stanley, A. Bolet, A. M. Bauer, J. S. Arias, A. Čerňanský, J. J. Bevitt, P. Wagner & S. E. Evans. 2020. Enigmatic amphibians in mid-Cretaceous amber were chameleon-like ballistic feeders. Science 370: 687–691.

[D07] Dixon, D. 2007. The Complete Illustrated Encyclopedia of Dinosaurs & Prehistoric Creatures. Hermes House: London.

[L00] Laurin, M. 2000. Seymouriamorphs. In: Heatwole, H., & R. L. Carroll (eds) Amphibian Biology vol. 4. Palaeontology. The evolutionary history of amphibians pp. 1064–1080. Surrey Beatty & Sons.

[LR95] Laurin, M., & R. R. Reisz. 1995. A reevaluation of early amniote phylogeny. Zoological Journal of the Linnean Society 113: 165–223.

[M93] Milner, A. R. 1993. Amphibian-grade Tetrapoda. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 665–679. Chapman & Hall: London.

[M06] Modesto, S. P. 2006. The cranial skeleton of the Early Permian aquatic reptile Mesosaurus tenuidens: implications for relationships and palaeobiology. Zoological Journal of the Linnean Society 146: 345–368.

[PS17] Pardo, J. D., M. Szostakiwskyj, P. E. Ahlberg & J. S. Anderson. 2017. Hidden morphological diversity among early tetrapods. Nature 546: 642–645.

[RCQ03] Ruta, M., M. I. Coates & D. L. J. Quicke. 2003. Early tetrapod relationships revisited. Biological Reviews 78: 251–345.

[S01] Seeley, H. G. 1901. Further evidence of the skeleton of Eurycarpus oweni. Annals and Magazine of Natural History, series 7, 7: 134–135.

[SBM11] Solomon, E. P., L. R. Berg & D. W. Martin (eds) 2011. Biology 9th ed. Brooks/Cole Cengage Learning.

[TC18] Triques, M. L., & M. L. Christoffersen. 2018. Arguments for replacing the concept of preadaptation by exaptation at the origin of terrestriality in Vertebrata. Biological Journal of the Linnean Society 123: 235–246.

[TT05] Tverdokhlebov, V. P., G. I. Tverdokhlebova, A. V. Minikh, M. V. Surkov & M. J. Benton. 2005. Upper Permian vertebrates and their sedimentological context in the South Urals, Russia. Earth-Science Reviews 69: 27–77.

Leave a comment

Your email address will not be published. Required fields are marked *